With the development of economy and the acceleration of urbanization process, domestic garbage and water pollution are increasingly becoming two major problems troubling people's daily life. A lot of efforts have been made to treat domestic garbage and water pollution; however, at present, domestic garbage and water pollution are treated separately at present.
For example, the treatment of domestic garbage is generally classified as landfill, burning, methane fermentation and recovery by sorting. Landfill treatment has the advantages of lower operation cost, simple process and less investment, but suitable garbage filling lands are becoming less and less; moreover, landfill treatment actually does not completely resolve the problem of the pollution of water and air. Burning is a technology widely used in the world and has the advantages of usable heat produced in burning, harmlessness to the earth and small occupation, while having the disadvantages of large investment, high operation cost, difficulties in burning due to high water content and low calorific value of the garbage, extremely low economical efficiency, difficult vent gas treatment, and easy occurrence of secondary pollution. Methane fermentation can produce combustible gas for use in electricity generation and heat supply, favoring harmless treatment of garbage, but has the disadvantages of complicated process and equipment, advanced operation and management, susceptible to climate, requirements for supporting construction of gas thermal power plant or gas supply pipes, insignificant effect in reducing the amount of garbage, and needs for landfill. Recovery by sorting has the highest resource utilization and recovery for non-combustible resources such as metal and glass, but is highly dependent on equipment, less economically efficient in difficult sorting, requires additional harmless treatment, and suffers from great energy consume and operation cost. Due to the limitations of each of the above garbage treatment processes, practical treatment processes are established by combining two or more of them based on system engineering to treat garbage.
As disclosed in Chinese Patent Publication CN101289336, garbage is pre-sorted into after pre-sorted garbage, plastic, fibers, and bricks and stones, which are then separately subjected to fermentation, composting and the like. However, the pre-sorting step is tedious for complicated process and long period treatment. Also, the waste water produced during garbage treatment should be treated in additional sewage treatment process. Chinese Patent Publication CN101537423 disclosed a domestic garbage treating method via steaming and then water separation. Firstly, the domestic garbage is loaded into a autoclave for steaming, and then the slurry formed by steaming the perishable garbage is discharged into a water separation tank, where the garbage is separated into three layers: light-weight garbage in the upper layer, slurry of perishable garbage in the middle layer, and heavy garbage in the lower layer, which are then separately treated. This process eliminates the complicated pre-sorting step, but prolongs the garbage treating period by adopting a steaming step, which increases treatment cost and thus is not suitable for large-scale garbage treatment, and easily cause secondary pollution due to untreated sewage after water separation.